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Error Checking
Demo — 15 pairs · 60s
How it works
Two values are shown side by side — a Reference and a Check.
Decide whether they match or contain an error as quickly as possible.
J
Same / Match
F
Error / Different
You can also tap the buttons on screen if you prefer.
Example
Reference
BA2394
Check
BA2394
→ Press J (Match)
Your assessment
Don't go in unprepared.
Most candidates only get one shot at the OPC. Those who practice the format beforehand report feeling significantly more in control — and score higher on reaction speed and accuracy.
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